I have limited Arabic knowledge, but I did work on one site using Arabic. All that was involved was putting the proper html header and IE displayed it properly. I don't see why you couldn't do this in Gossamer Mail, all the language is in a Language file, and the rest is just html templates.
Cheers,
Alex
--
Gossamer Threads Inc.
Cheers,
Alex
--
Gossamer Threads Inc.